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United States Patent | 5,515,382 |
Lassorie | May 7, 1996 |
An application specific integrated circuit that comprises a central processing unit and a plurality of devices which are dependent on the application of the integrated circuit and are connected to the central processing unit. At least one shift register is provided by connecting in series elementary cells each mounted on a respective line corresponding to an input/output line of the central processing unit, each cell being able to inject into its respective line a value entered serially through the shift register, and further being able to sample the value of the binary signal carried by its respective line with a view to a reading of this value through the shift register. A method is provided for using the shift register to test the makeup of the application specific integrated circuit, or an application program executing on the central processing unit.
Inventors: | Lassorie; Jean-Louis (Saint-Egreve, FR) |
Assignee: | SGS-Thomson Microelectronics S.A. (Pouilly, FR) |
Appl. No.: | 087925 |
Filed: | July 6, 1993 |
Jul 08, 1992[FR] | 92 08453 |
Current U.S. Class: | 714/730; 714/724; 714/736 |
Intern'l Class: | G01R 019/00 |
Field of Search: | 371/22.1,22.3,19,25.1 326/47,61,63,101 327/373,564,565 364/490,491 |
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5132974 | Jul., 1992 | Rosales | 371/22. |
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5239642 | Aug., 1993 | Gutierrez et al. | 371/19. |
5301156 | Apr., 1994 | Talley | 371/22. |
5379308 | Jan., 1995 | Nhuyen et al. | 371/22. |
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5428623 | Jun., 1995 | Rachman et al. | 371/22. |
Proceedings of the International Test Conference, Aug. 29-31, 1989, pp. 615-623, IEEE, New York, U.S., W. Harwood et al., "Testability Features of the MC68332 Modular Microcontroller". IEEE Transactions on Industrial Electronics and Control Instrumentation, vol. 36, No. 2, May 1989, New York, U.S., pp. 231-240, J.-C. Lien et al., "A Universal Test and Maintenance Controller for Modules and Boards". Proceedings of the Custom Integrated Circuits Conference, May 15-18, 1989, pp. 11.2.1-11.3.5, IEEE, New York, U.S., K. W. Lang et al., "A 16 Mbps Adapter Chip for the IBM Token-Ring Local Area Network". |
TABLE I __________________________________________________________________________ MODE MC0 MC1 MC2 BP0 BP1 STE TID TCI TDR TCA TIA PART 1/2 SLT __________________________________________________________________________ Sampling of the central 0 0 0 X X X 0 0 0 0 0 0 0 processing unit Sampling of the associated 1 0 0 X X X 0 0 0 0 0 1 0 devices Checking of the central 0 1 0 X X X 1 1 1 1 0 0 0 processing unit Checking of the associated 1 1 0 X X X 1 1 1 1 0 1 0 devices Fixing of a verification 0 1 1 X X X 0 0 0 0 0 0 1 address Sampling at the verification 1 1 1 1 0 0 0 0 0 0 0 f (WR) 0 address Instantaneous 1 1 1 1 1 0 0 0 0 0 0 f (WR) 0 Stepped 1 1 1 0 1 0 0 0 0 0 0 f (WR) 0 Automatic test 1 1 1 0 0 1 0 1 0 0 0 0 0 __________________________________________________________________________